Does the UK know whether I am currently there or not?

I had a tough time with this. Lets say you need to provide evidence of residence for the past five years (which is what I had to do). You have to have no more than 450 days absence in the 5 years, and no more than 90 days in the final year of that five years.

Well, my issue was I travelled a lot. And I regularly spent 3+ months overseas (during winter). So I had to stay in the country and not leave until I’d reduced my absence for the last year down to <90 days.

As for collating the information, I used my old passports, bank statements, photos… anything that let me figure out when I’d travelled, and when I’d returned. Then collated all that information in a spreadsheet and figured out how many days I’d been resident/absent.

Just do your honest best to recall each and every trip and you should be fine.

Note: this question was later cross-posted in Expats with the result of further information being available. Those interested should visit the cross-posted question at UK immigration application: Evidence / Proof that I lived there (EU citizen, no passport stamps)

Just curious if they keep track of me entering / exiting the UK and
whether that’s saved somewhere? I want to apply for citizenship, and
will be asked to provide information on my travels / when I was
abroad, but would have thought they could probably check this
themselves?

Yes, they keep track of your movements. BUT… In your case (i.e., you contemplate a nationality application), the answer is irrelevant. The onus is on you to support your nationality application with high quality evidence. There is no chance they will look it up for you.

Other answers have suggested using a Subject Access Request to obtain entry/exit dates. This is valid pathway to recover some of the information the government may have, but it should never be thought of as the complete history on a person’s movements, and worse, they do not have to honour the request if they don’t want to. Landing cards are perishable anyway.

If you think your travel records are incomplete you can submit an SAR and hope for a good outcome; otherwise the first substantiated (and legible) passport stamp you can produce will have to do.

Also, other answers and comments have pointed out that the UK subscribes to the Advanced Passenger Information scheme, and this point is uncontested. However, that data belongs to THEM, and they will never produce it for a specific individual. The data is governed by the DPA and not generally subject to individual FOI requests.

TL;DR

If you want a successful nationality (or ILR) application, keep scrupulous records of your movements and be able to substantiate your claims with high quality evidence. Hopefully something more substantial than boarding passes because caseworkers have been challenging those (and winning).

What makes this topical for us here on Travel is that a person’s start date can be placed when someone was here as a visitor or tourist! Factoid. Nothing in the regulations prevent this and people will use this “loophole” when they can benefit from it.

Extra note about intervals and dates

One of the biggest causes of failed British nationality applications is determining the person’s start date. It’s slightly counter-intuitive, but to summarise…

1. Take the date the person’s application was stamped in the mail room
   at the Directorate in Liverpool and that’s the end date.
2. Subtract exactly six years from the end date (three for spouses)
   and that’s the start date. Subtract exactly 1 year from the person’s end date and that’s their no-time-limit date.

Specifying the start and end dates is not done by the applicant, it’s the caseworker who determines what the relevant dates are. It all hinges on when the application was stamped ‘received’ in the mail room.

For EU nationals they use the date on their permanent residence card as the ‘no-time-limit’ date and ‘impute’ the other dates. Once again, the dates are out of the applicant’s control.

If the person was not in the UK on both of those EXACT dates, the application will fail and be returned to the applicant, even if the applicant has been here for 10 years or more. The applicant does not ‘own’ the start and end dates and does not have any control over them, instead they are derived by calculation.

That’s why spouses who originally transited through Dublin go manic-panic at application time because they have an ambiguous start date and hence cannot successfully apply for nationality. We have had questions about it on this site (and at Expats) and consistently advise spouses to channel hop so that they have a UK stamp to rely upon.

Another key difference is that there are “immigration rules” and “nationality regulations“, and a big difference between the two (at least to me… and the caseworkers in Liverpool). “Rules” versus “regulations” is something they take seriously so there is no scope for discretion in the nationality regulations, the regulations are not subject to human rights or similar challenges like the immigration rules are. A person can go to court to challenge the immigration rules and win permanent residence in the UK for example, but the courts will never grant a British passport.

Nationality guidance is at AN Booklet

See also Do the immigration agencies of EU member states keep records of EU citizens entry/exit from the Schengen zone?

See also What happens when someone inadvertently enters the UK without a landing interview?

See also Is the UK planning to introduce exit checks in 2015?

See also ILPA’s torn and bedraggled copy of the Precedent Based Scenarios. It will delight extreme nit-pickers and corner-case enthusiasts.

Note: this, and other questions prompted by Brexit, can get more information from The UK has voted to leave the EU. How does Brexit affect people traveling to the UK and vice-versa? and the links therein.

See also House of Lords debate on EU Citizens.

The UK electronically collects information of all passengers entering and exiting. When entering, you clear immigration whereby your entry is recorded. When exiting by air, the airline sends the passenger info to the Border Force, while if exiting by land (other than to Ireland), you clear immigration at the ferry port or train station.

So yes, the Home Office (the UK’s ministry of interior) will know if you’re here or not.

If you Need to get a hard copy of the information, make a SAR request to the Border Force, by writing a letter to:

Lunar House

11th floor Long Corridor

40 Wellesley Road

Croydon

CR9 2BY

stating that you wish an extract of your record of entries and exits to/from the UK.